Any Hornady rounds through it? Maybe 125 gr Critical Defense..seems like almost every ti cyl erosion I hear about has used that round at some point..I steer clear of Hornady in titanium cylinders. How about a bronze brush? You clean it with anything other than nylon brushes? This is one of my pet peeve problems.. Neither of my 340s have had a issue and I put a lot through them but clean very carefully..I know you said your j frame has not shown any problems.. Just a bugger of a issue..